1. Field of the Invention
This invention relates to polymeric viscosity index (V.I.) improvers useful as additives in petroleum oils, particularly lubricating oils, to concentrates containing said additives, and to methods for their manufacture and use. The present V.I. improver additives comprise a generally known class of V.I. improvers which have been post-treated by reaction with a lactone, preferably a C.sub.5 -C.sub.9 polymerizable lactone. The V.I. improvers which are to be lactone modified in accordance with the present invention comprise, for example, a copolymer of ethylene with one or more C.sub.3 to C.sub.28 alpha-olefins, which has been grafted with acid moieties, e.g. maleic anhydride, and then reacted with a mixture of an acid component, and a polyamine having two or more primary amine groups. In the alternative, the acid component may be prereacted with the polyamine to form salts, amides, imides, etc. and are then reacted with the grafted olefin polymer.
2. Prior Art
The concept of derivatizing V.I. improving high molecular weight ethylene copolymers with acid moieties such as maleic anhydride, followed by reaction with an amine to form a V.I. dispersant oil additive is known in the art as indicated by the following patents.
U.S. Pat. No. 3,316,177 teaches ethylene copolymers such as ethylene-propylene, or ethylene-propylene-diene, which are heated to elevated temperatures in the presence of oxygen so as to oxidize the polymer and cause its reaction with maleic anhydride which is present during the oxidation. the resulting polymer can then be reacted with alkylene polyamines.
U.S. Pat. No. 3,326,804 teaches reacting ethylene copolymers with oxygen or ozone to form a hydroperoxidized polymer, which is grafted with maleic anhydride, followed by reaction with polyalkylene polyamines.
U.S. Pat. No. 4,089,794 teaches grafting an ethylene copolymer with maleic anhydride using peroxide in a lubricating oil solution, wherein the grafting is preferably carried out under nitrogen, followed by reaction with polyamine.
U.S. Pat. No. 4,137,185 teaches reacting C.sub.1 to C.sub.30 monocarboxylic acid anhydrides, and dicarboxylic anhydrides, such as acetic anhydride, succinic anhydride etc. with an ethylene copolymer reacted with maleic anhydride and polyalkylene polyamine to inhibit cross linking and viscosity increase due to further reaction of any primary amine groups which are initially unreacted.
U.S. Pat. No. 4,144,181 is similar to 4,137,185 in that it teaches using a sulfonic acid to inactivate the remaining primary amine groups when a maleic anhydride grated ethylene-propylene copolymer is reacted with a polyamine.
U.S. Pat. No. 4,169,063 discloses reacting an ethylene copolymer in the absence of oxygen and chlorine at temperatures of 150.degree. C. to 250.degree. C., with maleic anhydride followed by reaction with polyamine.
U.S. Pat. No. 4,132,661 discloses grafting ethylene copolymer, using peroxide and/or air blowing, with maleic anhydride, and then reacting the grafted copolymer with a primary-tertiary diamine.
U.S. Pat. No. 4,160,739 teaches an ethylene copolymer which is grafted, using a free radical technique, with alternating maleic anhydride and a second polymerizable monomer such as methacrylic acid, which material are reacted with an amine having a single primary, or a single secondary, amine group.
U.S. Pat. No. 4,171,273 discloses reacting an ethylene copolymer with maleic anhydride in the presence of a free radical initiator and then with mixtures of C.sub.4 to C.sub.12 n-alcohol and amine such as N-aminopropylmorpholine or dimethylamino propyl amine to form a V.I.-dispersant-pour depressant additive.
U.S. Pat. No. 4,219,432 teaches maleic anhydride grafted ethylene copolymer reacted with a mixture of an amine having only one primary group together with a second amine having two or more primary groups.
U.S. Pat. No. 4,517,104 discloses V.I. improving ethylene copolymer, such as copolymers of ethylene and propylene or ethylene, propylene and diolefin, which are reacted or grafted with ethylenically unsaturated carboxylic acid moieties, preferably maleic anhydride moieties, and reacted with polyamines having two or more primary amine groups and a carboxylic acid component, preferably alkylene polyamine and alkenyl succinic anhydride such as polyisobutenyl succinic anhydride. The V.I. improvers disclosed in U.S. Pat. No. 4,517,104 also exhibit varnish inhibition and dispersancy properties.
The concept of polymerizing lactones having 6 to 10 atoms in their ring structure is also well known. For example, it is known that polymers of valerolactone or E-caprolactone can be prepared by reacting the lactone monomer with a hydroxyl or amine initiator. When reacting E-caprolactone, for example, the polymerization reaction may be illustrated by the following equations: ##STR1##
The reactions are known to be catalyzed by various esterification catalysts such as stannous octanoate, and a variety of different molecular weight products are feasible depending upon the ratio of lactone to initiator. Molecular weights on the order of from a few hundred up to about 5,000 are reproducably achievable.
Caprolactone can also be polymerized to a very high molecular weight, e.g., on the order of 100,000 or more. Typically such high molecular weight polymers do not employ initiators and preservation of functionality is not a requirement.
It is also known to react a lactone such as E-caprolactone with a polyol to form polyesters having terminal hydroxyl groups which are useful as plasticizers.
Other disclosures which relate generally to the polymeriztion of lactones and/or to the reaction of non-polymerizable lactones with fuel and/or lubricating oil additives are known as is illustrated by the following patents:
U.S. Pat. No. 4,645,515 discloses polyamine alkenyl or alkyl succinimides which have been modified by treatment with a lactone to yield polyamino alkenyl or alkyl succinimides wherein one or more of the basic nitrogens of the polyamino moiety is substituted with a hydroxyalkylene carbonyl group. The additives so disclosed are useful as dispersants in lubricating oils, gasolines, marine crank case oils and hydraulic oils.
U.S. Pat. No. 4,362,635 discloses synthetic ester oils which are esterification products of monoalcohols and dicarboxylic acids or of polyhydric alcohols and monocarboxylic acids respectively, containing 5 to 45% by weight of units of hydroxycarboxylic acids obtained from aliphatic alcohols, aliphatic, cycloaliphatic or aromatic carboxylic acids, and lactones of aliphatic C.sub.5 -C.sub.12 hydrocarboxylic acids. The synthetic ester oils are suitable for the preparation of lubricants and lubricant compositions.
U.S. Pat. No. 2,890,208 discloses a process for polymerizing lactones to form lactone polyesters that are useful as plasticizers.
U.S. Pat. No. 4,062,786 and its continuation-in-part (U.S. Pat. No. 4,292,184) disclose lactone oxazoline reaction products of hydrocarbon substituted lactone carboxylic acids such as polybutyl lactone carboxylic acid, with a 2,2-disubstituted-2-amino-1-alkanol such as tris-(hydroxymethyl) amino-methane (THAM). The reaction products and their derivatives are disclosed as being useful additives in oleaginous compositions such as sludge dispersants for lubricating oil.
U.S. Pat. No. 4,379,914 and its continuation-in-part (U.S. Pat. No. 4,463,168) disclose the preparation of polycaprolactone polymers by reacting E-caprolactone with a diamine wherein one of the amine groups of the diamine is a tertiary amine and the other is a primary or secondary amine. The polycaprolactone polymers are disclosed as being useful for neutralizing certain sulfonic acid-containing polymers to form amine-neutralized, sulfonated derivatives which can be combined with an alkyl benzene sulfonic acid to give a surfactant which contains ester groups, hydroxyl groups and amine-neutralized sulfonate groups.
U.S. Pat. No. 3,169,945 discloses the preparation of lactone polyesters which are useful as plasticizers and as intermediates for preparing elastomers and foams. The polyesters can be prepared by reacting a lactone such a E-caprolactone with an initiator such as an alcohol, amine or amino alcohol.
While there are a number of prior art disclosures relating to polyalkenyl succinic acid or anhydride type dispersants, in general, little or no prior art of direct pertinence appears to have surfaced in regard to the present lactone modified V.I. improvers. Exemplary of the patent literature which relates to oil soluble polyalkenyl succinic acid or anhydride type dispersant additives are the following U.S. Patents:
U.S. Pat. No. 3,950,341 relates to oil soluble detergent dispersants which are prepared by reacting a polyalkenyl succinic acid or its anhydride with a hindered alcohol such as pentaerythritol, and then with an amine.
U.S. Pat. No. 3,708,522 relates to lubricating oil additives which are oil soluble, mono- or polycarboxylic acid esters which are post-treated with mono- or polycarboxylic acylating agents. Esters of polyisobutenyl-substitued succinic anhydride and pentaerythritol post-treated with maleic anhydride exemplify the process and compositions disclosed in this patent.
U.S. Pat. No. 4,169,836 discloses reacting hydrocarbon substituted dicarboxylic acids, esters, or anhydrides, for example, octadecenylsuccinic anhydride and polyisobutenyl succinic anhydride with 2,2-disubstituted-2-amino-1-alkanols, for example, THAM, to form oxazoline products which are useful as additives in oleaginous compositions, such as sludge dispersants for lubricating oil.
U.S. Pat. No. 4,017,406 discloses carboxylate half esters of 1-aza-3,7-dioxabicyclo[3.3.0]oct-5-yl methyl alcohol which are the reaction products of long chain dicarboxylic anhydrides, such as polyisobutenyl succinic anhydride, and aldehyde/THAM adducts. The esters are useful as lubricating oil additives, friction modifiers and the like, depending upon the molecular weight. The disclosure of this patent is expressly incorporated herein by reference.
U.S. Pat. No. 4,102,798 relates to all soluble oxazoline reaction products of polyisobutenyl succinic anhydride and THAM which are useful additives in oleaginous compositions, such as sludge dispersants for lubricating oil or gasoline.
U.S. Pat. Nos. 4,113,639 and 4,116,876 disclose an example of alkenyl succinic anhydride having a molecular weight of the alkenyl group of 1,300 and a Saponification Number of 103 (about 1.3 succinic anhydride units per hydrocarbon molecule). This alkenyl succinic anhydride may be reacted with polyamine and then boric acid (U.S. Pat. No. 4,113,639), or may be reacted with an amino alcohol to form an oxazoline (4,116,876) which is then borated by reaction with boric acid.
U.S. Pat. No. 3,219,666 discloses as dispersing agents in lubricants, derivatives of polyalkenyl succinic acids and nitrogen compounds, including polyamines. The preferred molecular weight of the polyalkenyl moieties is 750-5,000.
U.S. Pat. No. 4,234,435 discloses as oil additives, polyalkylene substituted dicarboxylic acids derived from polyalkylenes having a M.sub.n of 1300 to 5,000 and containing at least 1.3 dicarboxylic acid groups per polyalkylene. In Example 34 of that patent, a polyisobutene-substituted succinic acylating agent is reacted with caprolactam in the presence of mineral oil and sodium hydroxide.
U.S. Pat. No. 3,381,022 relates to ester derivatives of substantially saturated polymerized olefin-substituted succinic acid wherein the polymerized olefin substituent contains at least about 50 aliphatic carbon atoms and has a molecular weight of about 700 to 5,000. The esters include the acidic esters, diesters, and metal salt esters wherein the ester moiety is derived from monohydric and polyhydric alcohols, phenols and naphthols. The ester derivatives are useful as additives in lubricating compositions, fuels, hydrocarbon oils and power transmission fluids. A related application, i.e., U.S. Pat. No. 3,522,179, relates to lubricating compositions comprising a major amount of a lubricating oil and a minor proportion of an ester derivative of a hydrocarbon-substituted succinic acid sufficient to improve the detergency of the lubricating composition. The ester dervatives are similar to those described in U.S. Pat. No. 3,381,022 and contain at least about 50 aliphatic carbon atoms. The hydrocarbon substituent may be derived from a polymerized lower monoolefin having a molecular weight of from about 700 to about 5,000.
U.S. Pat. No. 4,502,970 discloses lubricating oil compositions useful in both gasoline engines and diesel engines. The compositions contain a polyisobutenyl succinicimide as a supplemental dispersant-detergent in combination with another conventional dispersant. The polyisobutenyl group has a M.sub.n of about 700-5,000.
U.S. Pat. No. 4,680,129 relates to polyamino alkenyl or alkyl succinimides wherein one or more of the nitrogens of the polyamino moiety is substituted with: ##STR2## wherein R.sub.4 is alkylene of from 1 to 6 carbon atoms; m is an integer of from 0 to 2; R.sub.5 is alkylene to from 2 to 5 carbon atoms; p is an integer of rom 1 to 100; R.sub.6 is selected from the group consisting of hydrogen and hydrocarbyl of from 1 to 30 carbon atoms; and with the proviso that if m is one or two then R.sub.6 is hydrogen. The disclosed materials are additives which are useful as dispersants in marine crankcase oils, hydraulic oils, and lubricating oils. The examiner's attention is directed to the disclosure at column 9 where in Formula Ia there is shown the product formed by reaction of excess glycolic acid.
All of the above discussed patents are expressly incorporated herein by reference in their entirety.